What made you go to TWINS?

[tdecosta]

There are very good options available for single turbo upgrades for the 2004. 5 trucks. By "good" I mean that vendors understand the needs for durability/reliability, drivability, high power increases, lowering EGT's, ease of installation, quick spooling, etc.



Having said that, I'm ready to do a twin turbo set up if this is necessary for avoiding turbo lag in a high power motor. So, what do twins do that can't be accomplished with a single turbo? Is this done at the cost of drivability? I am willing to step up to the time and cost of twins, just asking if it is worth it. Thanks for responding.



TD

 

[robertyoke]

I am really liking my twins so far. back tires not liking twins. :-laf

I am still in the testing stage with this set up and the power is incredable over just the b1-03 single, the egt's don't compare with the twins when towing.
-robert

 

[OT-OF-HERE!!]

Twins

I am really liking my twins so far. back tires not liking twins. :-laf



I am still in the testing stage with this set up and the power is incredable over just the b1-03 single, the egt's don't compare with the twins when towing.

-robert

Whose did you go with? How much? How is fit and finish? What turbos are used? When you say egts don't compare,... how much lower than your single are they with comparable load and terrain?

 

[Jeff_K]

He built his own twins. I hope to try something similar this summer.



https://www.turbodieselregister.com/forums/showthread.php?t=123316

 

[Mark_Kendrick]

. So, what do twins do that can't be accomplished with a single turbo? Is this done at the cost of drivability? I am willing to step up to the time and cost of twins, just asking if it is worth it. Thanks for responding.



TD

I went to twins because big singles were laggy and fast spooling singles couldn't control EGTs at levels WELL above 400hp while towing.



with a properly designed set of twins...



With singles you are always trading faster spool for lower EGTs. With compounded chargers you get a top side better than a big single and a bottom end about as fast as you smallest charger is alone. Basically it spools like mad and tears your head off all the way to the redline



'Twins' allow you to spool a charger that your enginge normally couldn't then use it to precompress the air for your secondary charger. This gets higher pressures and cooler air charges than most any single charger could do alone. You run off the little charger at low rpm and/or load. Then once the motor is flowing enough to spool the big charger, the big charger compresses the air fed to the inlet of the little charger effectively growing it. Ratings on turbos are based on near atmoshperic pressure a the compressor inlet. If you increase the pressure at the inlet the total flow capability of the turbo is increased by by a factor of the input pressure divided by ambient pressure.



You also get lower drive pressures at elevated pressures (above 40~45 psi). Most single chargers fall off drastically in efficiency above ~45psi. their drive pressures start to greatly exeed boost pressure. This is the time when charge air temps start to rise dramatically. Imagine an air compressor supplying 45+psi at 320+cfm(3000rpm for a 5. 9l motor) in a single stage of compression.



FWIW,

Mark

 

[Matt400]

Does everyone with twins- "O" ring or Fire Ring their heads and run big pressure or can twins be used with lower pressures and not go into the engine?

 

[banshee]

Went twins for the power, drivability, durability, and cool factor



I'm currently running on the stock head gasket and stock bolts and haven't had an issue. A set of studs would probably add a little insurance, but the CR gaskets are pretty tough.



John

 

[Matt400]

I'm currently running on the stock head gasket and stock bolts and haven't had an issue.

What boost pressures do you see?

 

[Mark_Kendrick]

~55psi should be safe. you can run more boost with twins than a single because the twins don't have the high drive pressure problems that singles do.

 

[Gary - K7GLD]

At what PSI point do you start really crowding the intercooler efficiency - and what are the alternatives when you do?

 

[robertyoke]

~55psi should be safe. you can run more boost with twins than a single because the twins don't have the high drive pressure problems that singles do.

twins don't have as high egt's also, which takes stress off the head gask.

 

[robertyoke]

Whose did you go with? How much? How is fit and finish? What turbos are used? When you say egts don't compare,... how much lower than your single are they with comparable load and terrain?

I'll post more info as I get it, just working the bugs out right now.

egt's were safe with tst box on 2 tq and 5 hp with single (b1-03) under1400
had box reflashed and egt's on 9/9 may be safe to tow????... ... the egt's now mid 1200

I was towing my forklift to day and 9/9 will push boost to over 60 psi
back pressure and boost gauge peged at the same time. egt's 1250 or so.
I could not stay on the throttle very long, gcvw of 30k does not maneuver well and those little cars are always in the way.

 

[BCarmicle]

I went to twins for more power, lower EGTs, which will result in greater durability, and to avoid lag.



I wouldn't recommend going over 55-60lbs. of boost because it doesn't seem to produce more power at this level.



I would also always recommend using blow-off valves even if wastegated. I popped the headgasket at only 60lbs. when I cranked the bov all the way open.



Brandon

 

[mattymac]

I would also always recommend using blow-off valves even if wastegated. I popped the headgasket at only 60lbs. when I cranked the bov all the way open.



Brandon

I have heard that BOV can damage turbo(s) because if they open and disscharge the boost psi they can overspool the turbo(s)?

 

[BCarmicle]

I have heard that BOV can damage turbo(s) because if they open and disscharge the boost psi they can overspool the turbo(s)?

I don't know. I just know what happened when I opened them up to where they would not let out any boost and the hg popped.



I've heard to always use the BOVs, but then I have seen twins that do not have them. I consider them to be an insurance piece. I also have an external wastegate.



Brandon

 

[Patriot_RAM]

At what PSI point do you start really crowding the intercooler efficiency - and what are the alternatives when you do?

If anybody knows the answer to the intercooler question, I would really like to know. Somebody I know actually asked me if the intercooler would be a bottleneck in airflow. I've never heard of it happening on the 3rd gen, but for those of you up in the 600-800hp range -- what is your experience with this?



Thanks!

 

[Matt400]

If anybody knows the answer to the intercooler question, I would really like to know. Somebody I know actually asked me if the intercooler would be a bottleneck in airflow.

Hey David,

I don't know but from what I have read your 04 has plastic tanks on the side that have been known to let loose at 40 psi. Its also been mentioned that if the 03 fellas damage one and need a replacement they will be "upgraded" to plastic if you buy OE.

 

[jwilliams3]

05's have the plastic ends.

 

[Patriot_RAM]

The plastic tanks started showing up on the very late '04 or early '05. I'm not 100% sure which, but most of the '04MY that I have seen do not have the plastic tanks. I'm lucky! My '04 was manufactured in September of '03. I heard the same thing about the plastic tank superceding as a replacement for the '03 and '04 also. Given that, I'm sure that somebody will come out with an aftermarket intercooler.

 

[24V-DSL]

Intercooler

http://www.citydiesel.net/catalog/Dodge/intercooler.php